Internal-combustion engines



Jan. 10, 1956 D. B. MoRToN ET AL INTERNAL-COMBUSTION ENGINES `I5 Sheets-Sheet l Filed April 20, 1953 Inventors D. 13H optan? 51. llozozz/Jfp Jan. 10, 1956 D. B. MoRToN ET AL INTERNAL-COMBUSTION ENGINES 5 Sheets-Sheet 2 Filed April 20, 1953 Jan. 10, 1956 D. B. MoRToN ET AL 2,730,087

INTERNAL-COMBUSTION ENGINES Filed April 20, 1953 3 Sheets-Sheet 3 F/GZ nted States Patent O INTERNAL-COMBUSTION ENGINES Digby B. Morton, Digby B. Morton, Jr., and Graeme E. Morton, Kilbirnie, Wellington, New Zealand Application April 20, 1953, Serial No. 349,834

Claims priority, application New Zealand May Z, 1952 7 Claims. (Cl. 123-51) This invention relates to reciprocating internal combustion engines of the opposed piston type wherein the power is transmitted from each opposed piston through a kinematic chain to a driven member or members, such, for example, as a common rotating crank shaft; and is particularly though not solely of use in two cycle compression ignition engines of this type.

It is known that internal combustion engines of the type described possess thermodynamic advantages, particularly in the case of two cycle compression ignition engines of this type, but in present engines of the type described, disadvantages exist in that the kinematic chains connecting the pistons to the driven member or members have disadvantages, for example being unduly complicated or expensive to manufacture. Furthermore, such engines are not compact and must be built larger and heavier than would otherwise be necessary in order to accommodate the kinematic chains.

lt is therefore an object of the present invention to provide an internal combustion engine and preferably a two cycle compression ignition engine, of the type described, which is simple in construction and therefore cheap to manufacture, and which is compact in size compared with present engines of this type.

It is a further object of the present invention to provide an internal combustion engine of the type described which may be more easily dismantled and reassembled than present engines of this type.

lt is a still further object of the present invention in a preferred form to provide an internal combustion engine in which scavenging or charging air may be provided in sufficient quantity to give eicient scavenging and charging in a simple and convenient manner.

Accordingly in one aspect the invention consists in an internal combustion engine of the type described, wherein the kinematic chain connecting each piston to the driven member or members includes an oscillating lever which is so slidably associated with said piston that said lever will oscillate when said piston reciprocates.

In a further aspect the invention consists in an internal combustion engine of the type described, wherein the kinematic chain connecting each piston to the driven member or members includes an oscillating lever, which is so associated with said piston intermediate of the length of the piston, that said lever will oscillate when said piston reciprocates.

An advantage of the invention in its preferred form resides in the automatic allowance for misalignment between the cylinder and the crankshaft by the means used to connect the pistons, the gudgeon pins and the rocker arms. Y

One preferred form of the invention will now be described with reference to the accompanying drawings in which:

Figure l is a vertical cross-section on the line 1 1, Figure 2, of an engine constructed according to the invention, Y n

Figure 2 is a vertical cross-section on the line 2-2,

Figure l, the connecting rods being omitted and some parts being shown in elevation,

Figure 13 is a section of a piston and its associated oscillating lever on the lines 3 3, Figure l,

Figure 4 is a fragmentary side view, partly in broken lines, showing the securing means for securing the top cover,

Figure 5 is an enlarged detail of said securing means,

Figure 6 is a side elevation, showing the exhaust passage clip, and

Figure 7 is a pictorial view of the clip.

In the embodiment shown in the drawings, a cylinder 1, open at both ends, has two pistons 2 slidably mounted therein. Each piston has a dat face at either end separated by the length of the piston and the outer faces 3 of the pistons coact with the outer ends -b of the cylinder to form a scavenging or charging air pump for the engine. Since there is no restriction en the diameter of the outer faces 3 of the pistons and the outer ends 1b of the cylinder imposed by the construction of the engine, an improved performance of the engine is possible if the outer faces 3 of the pistons are made somewhat larger in diameter than the working face 4 of the pistons 2, as shown in Figure l of the drawings. The relative proportions of the outer faces 3 and the working faces 4 of the pistons are of course a matter for the designer of a particular engine to give a desired scavenging or charging air pressure.

The part la of the cylinder and the working faces 4 f the pistons are designed relative to each other to have a common working clearance. A plurality of piston rings 2a are provided in circumferential grooves near the working face i of the piston, in the well known way for the usual purpose. rEhe surface of the piston 2b adjacent to the working face 4 of the piston ccacts with the cylinder wall to form a front guide means to assist in guiding each piston while it reciprocates. The wcrl.- ing faces i of the pistons and the part of the cylinder 1a surrounding the working faces 4 and between said working faces form the combustion chamber of the engine.

Further piston rings 3a are provided in circumfertial grooves near the outer faces 3 of the pistons in the well known way. These piston rings 3a assist in increasing the efficiency of the air pump and the surface of the piston 3b adjacent to the piston rings 3a coacts with the cylinder wall to form a rear guide means to assist the front guide means in guiding each piston as it reciprocates, and for this latter purpose this surface 3b is spaced an appropriate distance from the working face 4 of the piston, for example the distance shown particularly in Figure l.

In the kinematic chain connecting each piston to the driven member or members, the latter comprising a rotating crank shaft 19, there is a gudgeon pin S pivot-ed in a bush 6 in each piston 2, the pivotal axis being transverse to the longitudinal axis of the piston and intermediate of the length of the piston, being substantially equidistant from the piston rings 2a and 3a, and being on a diameter of the piston. The gudgeon pin 5 is made of such a size as to allow a cylindrical aperture 7 to be bored therein (as shown particularly in Figure 3).

An oscillating lever 9 is associated with the piston Z by having a cylindrical end 3 having a bronze bush 10 which is slidably ted within the aperture 7 of the gudgeon pin, the aperture 7 being normal to the longitudinal axis of the gudgeon pin 5.

The bronze bush 10 has a spiral oil groove (not shown) on its outer curved surface, which oil groove is fed from the oil bore 11 and the space 13. The bush 6 also has a spiral oil groove (not shown) cut in its curved surface which communicates with both the space 13 and an oil 3 bore 12 leading to an orifice 14, from which oil is squirted against the rear face 15 of the piston 2, thus aiding its cooling. The oil then drains to the crankcase 16a of the engine frame 16 (which crankcase is adapted to receive the oil) through a slot 17 in the wall of each piston and through slots 18 in the cylinder wall.

Each oscillating lever 9 also extends from the gudgeon pin 5 through the slot 17 in the piston and the slot 18 in the cylinder wall, into the crankcase 16a. The oscillating lever has of course a working clearance from the edges of the slots 17 and 18.

The remaining links in each kinematic chain connecting a piston to the rotating crankshaft 19, comprise a connecting rod 20 and a crank 21, the latter forming part of the crankshaft 19. The connecting rods 20 and cranks 21 are shown only diagrammatically in Figure 1. Each oscillating lever 9 fulcrums on a short shaft 22 on which it oscillates and the outer ends of the shafts 22 are mounted in stress members 23 which are arranged one on either side of the oscillating lever. The stress members 23 are of a high tensile steel or other suitable material cast into the engine frame 16 which is of a light alloy, e. g. aluminium.

The lower end 24 of each rocker arm has fitted thereto a stub shaft 25 which is parallel to the short shaft 22 and the connecting rod 20 movably connects each oscillating lever 9 to a crank 21 of the crankshaft 19, a pair of substantially opposed cranks 21 being provided.

The cranks may be at a slightly different angle from 180 to each other to enable the piston which uncovers the exhaust ports 40 to do this before the inlet ports 43 are uncovered. Other means of achieving this may of course be provided, for example, by lowering the axis of the crankshaft 19 below the line joining the axes of the pins 25 when the pistons are in their mid position.

The crankshaft 19 rotates in bearings 26-26a mounted in the engine frame 16, an oil seal 27 being provided as shown. Oil is contained in the lower part of the crankcase in the well known way as mentioned above, and is pumped therefrom by an oil pump (not shown) through a series of channels 84 and 20a in the crankshaft 19, and the connecting rods 20, the oil bore 11 in the oscillating levers 9, the space 13 and oil hole 12 in the pistons 2. These oil channels connect through orifices in the various links of the kinematic chain with the coacting surfaces interconnecting said links, the bearings themselves having suitable oil grooves cut in their surfaces. Some of the oil lubricates the bearings and some passes on to be squirted from the orifice 14 as described above.

A flywheel 28 is provided, driven by the crankshaft 19 and of suicient inertia to enable its momentum when rotated at a sutiicient speed, to return the pistons to the position where they receive the next power impulse. 4The flywheel also of course lessens the cyclical speed variations in the known manner.

The two oscillating levers 9 are allochirally similar, being so arranged that if the stub shaft 25 of the right hand rocker arm is on the same side as the viewer in Figure l, the stub shaft 25 of the left hand oscillating lever is on the opposite side to the viewer. Because the cranks 21 are opposed, when the crankshaft rotates, the two opposed pistons in each cylinder reciprocate, being guided in the cylinder by the coacting of the piston surfaces 2b and 3b with the cylinder wall, the pistons alternately approaching to and receding from each other.

The flywheel 28 has radial vanes 29 fitted thereto and the housing 30 for the flywheel (integral with the crankcase) has air outlets 31 in its periphery. An end cover 30a on the housing 30 has a V-shaped ange 32 and the housing 30 has a corresponding V-shaped flange 33. The end cover 30a is held in place by a clamp ring 34 whichV has suitable quick release means (not shown) for holding it in operative position on the anges 32 and 33.'

The -vanes 2 9 and the housing 30 form a cooling air Y 4 pump for circulating cooling air through the engine. The cooling air pump draws air through a finned passage 36 leading from the outer air through the crankcase 16u. The fins 37 and 37a fitted both within the crankcase and within the passage 36, assist in transferring heat from the lubricating oil in the crankcase to the air passing through the passage 36 to assist in cooling the engine. The air pump also draws air through an inlet 35 communicating with a chamber 38 surrounding the central portion of the cylinder 1 which is nned as at 39.

The chamber 38 communicates with the outside air through suitably placed apertures, and baffles (not shown) are provided to direct airflow over the top of the cylinder.

The cylinder is provided with a series of apertures 40 (already mentioned) which form the ports for the exhaust gases, the exhaust ports communicating with an exhaust ring 41 leading to an exhaust pipe 42. The exhaust ring is in two portions held by suitable clamps 41a (Figures 6 and 7) engaging lugs 41b on the exhaust ring 41 and lugs 42a on the exhaust pipe 42 to enable it to be removed and replaced in its position.

A further series of apertures 43 form the inlet ports for the scavenging and charging air which communicate with a circumferential groove 44 (Figure l), the side walls 45 of which are integral with the cylinder 1. A short cylinder 46 tits over the walls 45 and an aperture or apertures 47 are cut in a part only of the short cylinder 46 as will be referred to later.

A fuel injection equipment 48 which may be of a suitable known type is provided.

The engine frame 16 is adapted to support and locate the cylinder, as will now be described.

The engine frame 16 extends upwardly to the plane 49 only, this plane being a horizontal plane passing through the longitudinal axis and on a diameter of the cylinder. To support the cylinder in the upper part of the engine frame 16, ribs 50, 51, 52 and 53 are provided which coact with the cylinder as will now be described. The ribs 52 and 53 are each machined to provide a semi-circular depression of the same diameter as the outer diameter of the outer ends 54 of the cylinder. A groove is machined in both the outer ends of the cylinder and in the ribs 52 and 53 to take a rubber or the like resilient sealing ring 55. The rib 50 is machined to provide a semi-circular depression of the same diameter as the outer diameter of the short cylinder 46, the rib 50 and the cylinder 46 being each grooved to accommodate a sealing ring 56. The rib 51 is machined to provide a semi-circular depression the same diameter as the rib 50 and a flange 57 on the cylinder 1 is machined to this same diameter, the ange 57 and rib 51 being grooved to accommodate a sealing ring 56.

The centres of the semi-circular depressions of course lie on a line which coincides with the longitudinal axial centre line of the cylinder 1 when the latter is in place in the semi-circular depressions.

To locate Vthe cylinder longitudinally in the engine frame 16 a spigot 58 lits into holes drilled in both the cylinder wall and the engine frame 16, as shown. This allows thermal expansion and contraction of the cylinder 1 longitudinally, whilst preventing its movement as a whole. The spigot 58 is substantially the same axial distance longitudinally from either end of the cylinder 1. The spigot 58 may of course be fixed to either the engine frame 16 or to the cylinder 1. Other means to locate the cylinder may be provided, for example, either the cylinder, or the engine frame may have a circumferential flange tted thereon to coact with a corresponding groove in the other member.

It is to be noted also that the short shafts 22 are each substantially the same distance from the spigot 58 which is disposed substantially centrally laterally and longitudinally in the engine frame 16. Also as will be seen more particularly in Figure 3, the longitudinal axes of the oscillating levers 9 are on a line which lies on the vertical diameter of the cylinder 1, the rocker arms being therefore symmetrically located in the engine.

To hold the cylinder in position and to fulfil other purposes which will be described later, a top cover 59 is removably attached to the engine frame 16. The top cover has a at lower surface which ts on the plane 49 of the engine frame 16, some form of sealing means being provided between the two contiguous surfaces, for example, paper impregnated with a jointing compound. Four semi-circular sealing surfaces 60, 61, 62 and 63 are provided spaced apart at spacing such as to correspond with the ribs 50, 51, 52 and 53. Each of said surfaces and the cylinder 1 is grooved to take the sealing rings 55 and 56 as in the case of the ribs 50, 51, 52 and 53. The air pump formed by the coacting of the outer faces 3 of the pistons and the outer ends 54 of the cylinder 1 is operatively connected to the atmosphere and the combustion chamber as follows. A passageway 64 for the scavenging and charging air leads from one outer end 54 of the cylinder and a further passageway 65 leads from the other end 54 of the cylinder, both passageways communieating with the groove 44 through the apertures 47. As stated above the apertures 47 are in a'portion only of the periphery of the short cylinder 46 and this portion is within the passageway 64. The outer wall 66 of the top cover 59 forms one wall of both the passageways 64 and 65 and inner walls 67 and 68 complete the walls of the passageways.

An air inlet 69 having a spring loaded disc valve 70 is provided, the valve 70 allowing air to be drawn into the passageways 64 and 65 from the atmosphere but not permitting egress of air from said passageways to the atmosphere. It is to be noted that the seals 55 and 56 prevent the interchange of air between the passageways 64 and 65 and the outer atmosphere, the interior of the crankcase 16a and the cooling space 38.

Referring to Figures 4 and 5, the top cover 59 is removably attached to the engine frame 16, thus holding the cylinder 1 in position, by four linkages or toggle catches, one towards each end of the inside of the top cover on either side thereof. One such catch is shown in Figure 4. Each catch comprises a curved and hooked link 71 pivotally connected by a pivot 71a to a toggle lever 72, pivoted in turn at 72a to a curved link 72b pivoted in turn, at 72C to a link 72d pivotally mounted at 72e to the top cover 59. The hook of the hooked link 71 engages a pin 73 on the engine frame 16. The hooked links 71 are accessible through apertures 74 on each end of the crankcase 16a, the apertures '74 being covered by cover plates 75 (Figure l).

Other means of securing the top cover in position may of course be provided, for example the top cover may be bolted in place.

The cylinder 1 is releasably held in the top cover 59 by suitable means, so that the top cover and the cylinder are removed as a whole, with the pistons still inside the cylinder and with the exhaust ring 41 and exhaust pipe 42 still attached to the cylinder. If it is desired to remove the exhaust ring 41 this may be done at alater stage but because the pistons may be removed from the cylinder once the top cover 59 has been removed from the crankcase 16, removal of the exhaust ring 41 may not be necessary unless it requires replacing.-

So that the piston 2 may be removed endwise from the cylinder 1, flat circular discs 76 (Figure l) are held in grooves 77 in semi-circular apertures in the engine frame 16 and grooves 78 in semi-circular apertures in the top cover 59, seals comprising rubber rings 79 sealing the discs in the said grooves.

The semi-circular apertures in the top cover must have a greater diameter than the largest diameter of the pistons 2 to enable the latter to be withdrawn endwise from the cylinder 1 while the cylinder is still held within the top cover 59.

The fuel injection pump 48 is operated through a rocker arm 80, push rod 81 and cam follower 82 by a cam 83 rotating with the crank shaft 19.

The crankshaft is accessible for withdrawal by removing the caps of the bearings 26, 26a and the members 35 andv 36.

In operation, the crankshaft revolves, the oscillating levers fulcrum on the short shafts 22, thus oscillating over a short arc, and the ends 8 of the oscillating levers 9 slide slightly in the gudgeon pins 5 as the pistons 2 reciprocate, since the ends of the oscillating levers move in an arc of a circle while the gudgeon pins 5 are constrained by the movement of the piston, guided by the piston surfaces 2b and 3b in the cylinder 1, to move in a straight line, the gudgeon pins turning slightly in the bushes 6 in the pistons 2.

It is to be noted that since each link in the kinematic chain is constrained to move over a definite path, the kinematic chain is completely restrained.

Because the end 8 slides in the aperture 7 in the gudgeon pin 5, oil fills the space 13 then when the end 8 moves upwardly the oil is squirted through the oriiice 14 in spurts.

The engine may be dismantled for decarbonizing and the like by releasing the top cover 59 and limiting the said top cover and the cylinder l containing the pistons 2 vertically i. e. along a line at right angles to the longitudinal axis of the cylinder. The ends 8 of the oscillating levers 9 simply slide out of the apertures 7 in the gudgeon pins thus disengaging the pistons from the oscillating levers. The cylinder may then be moved clear of the engine frame and the pistons removed endwise from the cylinder, which may be left attached to the top cover.

Because of the sliding of the ends 8 of the oscillating levers in the gudgeon pins 5 and because of the rotation of the gudgeon pins in the piston bosses, the distance of each end of the cylinder above the crankshaft is not critical and some misalignment of the cylinder relative to the crankshaft in this respect may be accommodated without straining the engine.

The stress members 23 take the main dynamic stresses substantially linearly when the engine is running.

Suitable cast materials may be used throughout in the manufacture of the engine or the engine may be built up by welding or the like from rolled or other suitable mateh rials, or a mixture of the two may be used.

In the preferred form, the construction is such that the exhaust ports 4@ are nearer the longitudinal centre (on which the pin 53 lies) than the inlet ports 43, so that the exhaust ports maybe uncovered first on outward strokes of the pistons. With this construction, the direction of rotation of the engine may be reversed if desired, by reversing the cylinder 1 and top cover 59 end for end in the engine frame 16 and adjusting the cam 83 operating the fuel injector in order to inject the fuel at the correct time.

The axial centre of the gudgeon pin need not necessarily lie on a diameter of the piston, but may be slightly below it in order to enable the 'rocker arm to be shortened slightly;

It is of course obvious that although throughout this specification of which the claims .form part, the engine shown has been described as though the cylinder is in a horizontal plane with the crankshaft below it, other juxtapositions of these two members are possible, for example the cylinder may be vertically disposed or may be disposed horizontally below the crankshaft.

Although a single cylinder engine has been described in detail, it is obvious that the invention may be applied to a multi-cylinder engine.

Although scavenging and charging air has been provided in the above-described engine by the coacting of the outer faces 3 of the pistons 2 with the outer ends of the cylinder 1, any engineer skilled in the art would be able to adapt the engine as described to use other known means to provide such air. For example, a rotary blower may be used, in which case the cylinder 1 would be of the same internal diameter throughout its length and the piston rings 3a would be replaced by a single oil ring near the outer end of the skirt of the piston.

Also, although air cooling of the cylinder has been described, an engineer` skilled in the art could readily adapt the engine to water cooling.

We claim:

l. In an internal combustion engine of the type having a. cylinder, a pair of double acting opposed pistons in said cylinder, a gudgeon pin in each said piston, a connecting rod lever for each said piston slidably insertable into said gudgeon pin, a frame member to support said connecting rod levers and said cylinder, a cover removably attached to said frame member, said cover having a at lower surface for engagement with the said frame member to hold the said cylinder against motion, a plurality of sealing rings disposed between respective points of engagement, and a plurality of toggle catches to removably secure the said cover to the said frame whereby upon release of said toggle catches the said cylinder may be dismounted, said piston thereby removing from slidable engagement with said connecting rod.

2. The invention as set forth in claim l, wherein the respective said toggle catches comprise a rst hooked link, a toggle lever pivotally connected to said first hooked link, a second link pivotally connected to said toggle lever, a third link pivotally connected to said second link, said third link adapted to be pivotally connected to said cover, and a pin member secured to said frame member to be embraced by said first hooked link.

3. In an internal combustion engine of the type having an elongated cylinder and a plurality of pistons slidable therein, a gudgeon pin centrally mounted in each of said pistons, a frame member adapted to support said cylinder, means to locate said cylinder against endwise movement in said frame, kinematic chains in said frame including lever means slidably engaging said gudgeon pins in said pistons to transmit force therefrom and thereto, and lever operated tension means releasably secured to said engine frame to hold said cylinder against vertical motion whereby complete renovation of the engine may be made by release of said clamping means after which said cylinder is removable from said engine frame enabling disconnection of said pistons from said kinematic chains and quick replacement thereof by new parts.

4. In an internal combustion engine of the type having an elongated cylinder and a plurality of double acting pistons slidable therein, a gudgeon pin centrally mounted in each said piston, a frame member to support said cylinder, a lever means for each said piston connected' Within said frame to a connecting rod and crank having one end projecting into said cylinder to operatively engage said gudgeon pin, a cover removably attached to said frame member, said cover having a at lower surface for engagement with the said frame member to hold the said cylinder against vertical motion, a plurality of sealing an elongated cylinder and a-plurality'of double acting pistons slidably received therein, a gudgeon pin mounted centrally in each said piston, a frame member adapted to support said cylinder, lever means for each said piston mounted in said frame and projecting into said cylinder to engage said gudgeon pin, a cover lremovably attached to said frame member, said cover having a at lower surface for engagement with said frame member and said cylinder to hold the same against vertical motion, a plurality of sealing rings disposed between respectivepoints of engagement, and releasable clamping means to removably secure the said cover to the said frame whereby upon removal of said cover the said cylinder may be dismounted without use of wrenches or other tools.

6, In an internal combustion engine of the type'having an elongated cylinder and a plurality of pistons slidable therein, a frame member adapted to support said cylinder, lever means in said frame extending into said cylinder to engage said pistons to transmit forces from and to said pistons, a cover removably attached to said frame member, cylinder air inlet passages formed in said cover, said cover having a flat lower surface'for engagement with said frame member and concave surfaces to engage `said cylinder to hold the same against vertical motion, a plurality of sealing rings disposed in respective planes of engagement, and releasable clamping means to removably secure the said' cover to the said frame to permit rapid dismounting thereof without the use of tools.

' 7.I In an' internal combustion engine comprising a frame, 'a cover, a cylinder open at both ends cradled in arcuately concave webs of said frame and of said cover, two pistons slidably mounted in said cylinder each said 'piston presenting a Working face at each end separated by the length of said piston, the working faces presented inwardly toward each other dening the ends of the combustion chamber of the engine and the working faces presented outwardly coacting with a portion of the said frame and of said cover to form a scavenging air pump, means to drivingly connect said pistons to a rotatable shaft said means including a lever opposite each piston pivoted externally of said cylinder and extending into said cylinder to engage said pistons, and lever means to secure said cover to said frame said lever means being so constructed and arranged that securement or release is made without use Vof tools, whereby removal and replacement of said cylinder and pistons may be quickly performed.

References Cited in the le of this patent UNITED STATES PATENTS 

